1. The Field of the Invention
This invention relates to a reverse osmosis system for purifying water, and more particularly to such a system with provision for automatically flushing the membrane module.
2. The Prior Art
A number of reverse osmosis systems have been proposed or used which have included provisions for periodically flushing the membrane module. Flushing, using for example a temporarily unrestricted flow of feed water through the module, is effective to wash away salts and deposits which may have accumulated on the membrane surfaces. Flushing schedules may be automatic with suitable valves actuated by a timer, or may be manually accomplished after predetermined time intervals, or when membrane operating characteristics indicate the need.
Small household reverse osmosis units are valuable for producing a relatively small quantity of so-called "bottled water" quality water from a municipal supply. Such units must operate for long periods of time without service or attention and flushing procedures are helpful iin maintaining membrane efficiency. However, flushing equipment must be simple, automatic, reliable and inexpensive; sophisticated devices are unsuitable because of cost and complexity.